Medical specimens, for example, biological and non-biological fluids, solids and semi-solids, are routinely collected and analyzed in clinical situations for various purposes. In particular, biological fluids such as blood, urine, and the like are typically collected in a specimen collection container which is in the shape of an open-ended tube. Such a tube is generally in the form of an elongate cylindrical member having one end open and an opposing end permanently closed by an integral semi-spherical portion, with the tube defining an interior which collects and holds the specimen.
After a biological sample has been drawn and/or collected in the tube, the tube with the sample is typically transported to a clinical testing laboratory for analysis. For example, blood samples may undergo routine chemistry, hormone, immunoassay or special chemical testing. In order to conduct such testing, the sample is normally transferred from the primary tube in which the sample was collected into one or more secondary tubes for testing and analysis, oftentimes to effect simultaneous testing in two or more different areas. In order to minimize contamination, evaporation and spilling during transportation, analysis and storage, it is important to maintain the open end of the tube with a closure.
The open end of a specimen container is typically sealed by a resilient cap, a removable rubber stopper, or plastic film during transport and analysis. Such closures provide means for sealing the open end of the tube, but are not capable of being efficiently removed, stored and replaced without causing contamination and with the use of one hand, as is often desired in clinical environments. Furthermore, when using analytical testing equipment for testing biological samples, it is typically necessary to maintain the samples in an open container to allow a probe from the testing equipment to be inserted into the container. In view of these needs, it is desirable to have a closure that can be easily and repeatedly opened and closed for manual or automated access.
One particularly useful type of closure for containers is a ball and socket type closure. While a number of ball and socket type closures for various containers are known, none are entirely effective for use in specimen collection containers, where an adequate seal is essential.
For example, U.S. Pat. No. 2,032,776 to Van Ness describes a closure for a dispensing container including a valve ball having a bore which sits within a curved boss on a resilient disc having an opening into the container. The resilient disc, however, is constructed as a separate component, for example of stainless steel, as opposed to being integral with the boss/socket, and therefore creates a potential for an inadequate seal. Furthermore, the resilient disc is not capable of adequate flexing with rotative movement of the ball, and therefore does not provide for an adequate seal.
Accordingly, it is desirable to provide a closure for a specimen collection container which can be easily and repeatedly opened and closed and which can effectively provide an adequate seal.